FromSoftware closed Sunday Download multiplayer servers for Dark Souls: Remastered, Dark Souls 2, Dark Souls 3, and Dark Souls: Prepare to Die Edition. The reason should be a gross security flaw that allows other players to take control of your PC.
As pointed out via Reddit the error is a so-called Remote Code Execution variant – also called RCE. This allows external users to connect to a PC and do everything from extracting personal information to installing viruses.
Exactly how this is possible in Dark Souls is not yet widely known. However, the problem got a lot of attention when using Twitch The Grim Sleeper was apparently subjected to an RCE attack when he played Dark Souls 3 a few days ago.
Publisher Bandai Namco was quickly alerted to the error, and within a short time, the servers for all Dark Souls games were shut down. The concern among fans is now that Elden Ring has the same problem. As the development team is aware of the situation, there is admittedly some time to clean up before the launch on 25 February.
By the way, only the PC versions are affected. Players on PlayStation and Xbox can thus still play against each other without the risk of being hacked.